Abstract This proposed competitive revision to the NIDA grant 1 R01 DA046910, entitled ?Facilitating the Implementation of Interim Methadone to Increase Treatment Access: A Multi- Site Implementation Trial,? is in response to NIDA Notice NOT-DA-19-022 to establish an Addiction Medicine Practice-Based Research Network (AMNet) to address the urgent national opioid crisis. AMNet will be a collaboration among the American Psychiatric Association (APA), the American Society of Addiction Medicine (ASAM), and Friends Research Institute (FRI). It will build on the parent grant?s aims by expanding the focus of the study from opioid treatment programs to office-based opioid treatment. Expanding access to, and improving patient outcomes in, pharmacotherapy for opioid use disorder (OUD) is an important pillar of our nation?s response to the epidemic. Very little is known about OUD services and outcomes in the multitude of outpatient physician practices that provide addiction treatment. Importantly, these practices have not been harnessed for OUD treatment research. This project will leverage the power of the APA?s clinical data registry (PsychPRO) and the over 40,000 members of the APA and ASAM to fill these gaps by establishing AMNet, a practice-based network with an electronic registry to a serve as an opioid treatment research platform. The proposed project is multi-pronged. It will recruit practices and providers for AMNet primarily through ASAM and the APA. A Steering Committee will oversee the identification of standardized common data elements and measures relevant to OUD and its treatment. These will include both patient-reported and clinician-rated outcomes to be collected through PsychPRO. The proposal?s specific aims are: (1) establish AMNet; (2) adapt PsychPRO to support data collected for AMNet; (3) test AMNet measures and data elements; (4) expand addiction medicine research capacity and outreach, and (5) develop business requirements for linking AMNet to other databases and registries. The significance and innovation of the proposed study rests upon its creation of a novel research network to provide real-time data for researchers, clinicians, and policymakers on patient characteristics, care delivery, and patient outcomes. These data can be used to improve treatment effectiveness through performance improvement efforts. Importantly, AMNet will serve as a research platform for studies of comparative effectiveness, patient centered outcomes, and implementation studies.